When one makes a medium or long distance journey in any means of transport, the passengers frequently become sleepy as a result of inactivity. When sleep starts to occur, a relaxation takes place of the muscles of the neck and torso which leads to the head nodding or to its lateral rolling, along with poor positioning of the neck. All this gives rise to continual interruptions to sleep, which prevents any refreshing rest from being achieved. Moreover, the postures which the neck adopts are dangerous for the state of health of the cervical zone and can be much more serious in case of accident or a brusque maneuver of the vehicle, especially if this occurs during the said periods of muscular relaxation.
Some known devices for trying to reduce both the nodding of the head and the lateral rolling of it with respect to the back-rest of the seat and thereby improving rest during the journey include pillows and similar devices. The most popular of these is a pillow, inflatable or otherwise, with the shape of a horseshoe which rests on the shoulders and is positioned around the passenger's neck in order to support the head in a more or less vertical position. Nevertheless, it is known that said pillows do not provide sufficient support for the head which ends up being considerably inclined, with the consequent disturbance that this produces, especially in the neck. There exist other patented devices which aim to facilitate rest for the passenger by means of rigid elements such as those described in documents: U.S. Pat. No. 6,033,023, U.S. Pat. No. 4,881,777, U.S. Pat. No. 5,806,933, GB2415616, FR2883528, U.S. Pat. No. 7,204,557, US2003/0038521, FR2875752, EP1106427, JP200325149, US2001040401, U.S. Pat. No. 5,806,933, JP20066213253, U.S. Pat. No. 4,097,086, U.S. Pat. No. 5,868,471, ES2221767, WO2005/000629, GB2246292 and others which are based on the use of belts or bands which are applied to different parts of the head, like those described in the documents: FR2534125, CN1059690, US2004124685, DE9001789U1, GB1497847A and WO2007031153A2. None of the above documents shares the main characteristics of the present invention, in other words, that it concerns a mobile and suspended device from an independent suspension element located above the head, and instead they refer to non-suspended and rigid is elements or those which are attached directly to the fixed structure of the vehicle. Moreover, in the case of the aforementioned inventions which carry out a restraint of the head by means of belts or cords, the functioning axis of the restraint is horizontal and anterior-posterior, rather than being vertical, which substantially changes the way in which it works, the properties and, indeed, the resulting effect on the restraint of the head.
The documents technically closest to the present invention, due to sharing its suspended character in passenger vehicles, are: U.S. Pat. No. 1,837,406, U.S. Pat. No. 1,855,408, US70555A, US83227A and FR2720988A1, which are analyzed below.
The main differences between the document U.S. Pat. No. 1,837,406 and the present invention are the following:                1/ it comprises a complicated device for securing in the lower part of the seat which contrasts with the simple securing system in the upper part of the seat of the present invention.        2/ it does not comprise any frontal restraint element in its design and therefore there does not exist any mechanism which secures the head with regard to its forward movement, notably decreasing the safety of the passenger in the event of accident. On the contrary, the device of the present invention considers safety to be one of the priority objectives, and it therefore surrounds the head in order to improve its restraint, especially in front-on accidents, side impacts and sudden braking.        3/ it comprises a part of the metallic restraint structure that is located very close to the head and on both sides of the same, which notably affects the safety since the head could knock against the described metallic structure. Nevertheless, in the present invention, the rigid structure is at all times kept separate, above the head, and it has a safety mechanism that increases that distance more when the head becomes separated from its support.        4/ it comprises two attachment zones with the suspension system instead of one, unlike the preferred forms of embodiment of the present invention.        
The suspended devices described in documents U.S. Pat. No. 1,855,408, US70,555A and US83,227A have the following as their main differences compared to the present invention:                1/ they comprise a securing applicable solely to the roof of the vehicle or to a horizontal surface located above the passenger, and is not possible to is adapt it to the back-rest of the seat.        2/ they comprise an arrangement of the head and neck that is in general fairly horizontal compared to the characteristic vertical position of the present invention. In other words, the passenger has to be in a position that is more laying down than seated, thereby requiring a large space to be available around him or her so that such a posture can be adopted.        3/ they do not comprise any frontal restraint element in order to avoid the forward displacement of the head in the event of accident or brusque maneuver of the vehicle.        4/ they have a securing point that is far away in the roof, therefore the restraint response of the head of the passenger in terms of safety with regard to any brusque maneuver of the vehicle becomes excessively delayed, and is virtually null.        
The invention described in document FR2720988A1 comprises as its main differences with present invention:                1/ it has the objective of being used by drivers of racing cars rather than by passengers of a transport vehicle and in no case does it aim to improve the capacity for sleep and rest.        2/ it requires a helmet which is secured via its upper part to the suspension bar, in this way, and owing to the rigidity of the helmet and the excessive proximity between its securing point and the suspension bar, the response to displacement is too brusque and immediate, unlike the present invention where it is smooth and progressive. Sudden restraints in the movement of the helmet can generate a brusque jerk on the neck and produce serious injuries in the union between the neck and the head.        3/ it does not incorporate any safety mechanisms.        4/ the suspension plate is fixed to the chassis of the vehicle rather than to the seat, as occurs in the present invention.        
Finally, there exist other inventions which are not applicable to transportation vehicles but rather to domestic appliances which serve to facilitate the posture of people with physical impediments, or to systems for carrying out traction in patients with vertebral pathologies, like those described in documents U.S. Pat. No. 5,010,898A and U.S. Pat. No. 4,987,886A. A fundamental difference between the two documents and the present invention is that they do not describe any kind of safety mechanism nor its use in passenger vehicles. Moreover, the invention described in U.S. Pat. No. 5,010,898A reports on a securing made in the rear part of a seat, rather than in the upper zone thereof and a chin rest needs to be provided that will secure the head due to the fact that the vertical belt joining the helmet to said chin rest passes in front of the ears, a situation that does not occur in the present invention where the functioning axis passes behind the ears and is directed towards the lower part of the occipital zone of the head, the place where the head rests on the device, which produces a slight but sufficient tendency of the head to move backwards rather than forwards, and therefore no chin rest is necessary. Moreover, the invention described in document U.S. Pat. No. 4,987,886A is secured to the shoulders of the patient rather than to the back-rest of the seat, it requires the use of a pulley which is in no case necessary in the present invention, and it also comprises rigid elements on both sides of the head, which could be very traumatic if used in a vehicle.